It is desirable in many types of couplings to locate the field coil radially inwardly of both the inductor and rotor. It is further desirable to use a stationary mounting of the field coil on the housing of the coupling to avoid the slip rings and brushes associated with rotating coils. The support or mounting for the field coil is typically L-shaped, having one arm fastened to the housing of the coupling and a second arm, on which the coil is mounted extending inside the inductor and rotor. The flux of the field coil passes through the coil support in completing its magnetic circuit through the rotor, inductor, and air gaps of the coupling.
The configuration of couplings presently in use have not optimized the passage of flux through the coil support and particularly the passage of the flux between the support and adjacent portions of the rotor.
Further, while locating the field coil inwardly of both the inductor and rotor has electro-mechanical advantages, it becomes more difficult to dissipate the heat generated in the coil by its energization. Existing designs have not provided for adequate dissipation of the heat.